141 research outputs found

    A Fresh Approach to Forecasting in Astroparticle Physics and Dark Matter Searches

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    We present a toolbox of new techniques and concepts for the efficient forecasting of experimental sensitivities. These are applicable to a large range of scenarios in (astro-)particle physics, and based on the Fisher information formalism. Fisher information provides an answer to the question what is the maximum extractable information from a given observation?. It is a common tool for the forecasting of experimental sensitivities in many branches of science, but rarely used in astroparticle physics or searches for particle dark matter. After briefly reviewing the Fisher information matrix of general Poisson likelihoods, we propose very compact expressions for estimating expected exclusion and discovery limits (equivalent counts method). We demonstrate by comparison with Monte Carlo results that they remain surprisingly accurate even deep in the Poisson regime. We show how correlated background systematics can be efficiently accounted for by a treatment based on Gaussian random fields. Finally, we introduce the novel concept of Fisher information flux. It can be thought of as a generalization of the commonly used signal-to-noise ratio, while accounting for the non-local properties and saturation effects of background and instrumental uncertainties. It is a powerful and flexible tool ready to be used as core concept for informed strategy development in astroparticle physics and searches for particle dark matter.Comment: 33 pages, 12 figure

    A Unique Multi-Messenger Signal of QCD Axion Dark Matter

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    We propose a multi-messenger probe of QCD axion Dark Matter based on observations of black hole-neutron star binary inspirals. It is suggested that a dense Dark Matter spike may grow around intermediate mass black holes (103105M10^{3}-10^{5} \mathrm{\,M_{\odot}}). The presence of such a spike produces two unique effects: a distinct phase shift in the gravitational wave strain during the inspiral and an enhancement of the radio emission due to the resonant axion-photon conversion occurring in the neutron star magnetosphere throughout the inspiral and merger. Remarkably, the observation of the gravitational wave signal can be used to infer the Dark Matter density and, consequently, to predict the radio emission. We study the projected reach of the LISA interferometer and next-generation radio telescopes such as the Square Kilometre Array. Given a sufficiently nearby system, such observations will potentially allow for the detection of QCD axion Dark Matter in the mass range 107eV10^{-7}\,\mathrm{eV} to 105eV10^{-5}\,\mathrm{eV}.Comment: 5 pages, 3 figures. Appendix added with additional figures. Updated to published versio

    MIRU-VNTRplus: datenbankgestützte polyphasische Analyse von Mycobacterium tuberculosis complex Genotypisierungsdaten

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    Die molekulare Typisierung von Isolaten des Mycobacterium tuberculosis complex (MTBC) ist für viele epidemiologische Anwendungen von Bedeutung. Das Verfahren der Variable Number Tandem Repeats (VNTR) Typisierung wird hierzu immer wichtiger, da es sehr diskriminierend und sehr reproduzierbar ist. Bis jetzt gibt es noch keine Software zur Analyse von VNTR-Typisierungsdaten, die eine repräsentative und gut charakterisierte Referenzdatenbank beinhaltet. In die hier vorgestellte Datenbank wurden 187 Stämme der wichtigsten Lineages des MTBC aufgenommen. Für jeden dieser Stämme sind neben den Basisdaten auch VNTR-Daten für 24 Loki und vier weitere genetische Marker vorhanden. Benutzer können ihre Isolate auf zwei Arten mit der Referenzdatenbank vergleichen, durch Ähnlichkeitssuche oder durch Auswertung der Gruppierung in einem phylogenetischen Baum. Die für die Ähnlichkeitssuche notwendigen Schwellenwerte wurden durch eine Auswertung der Suchergebnisse für die Referenzstämme bestimmt

    Dark Matter Model or Mass, but Not Both: Assessing Near-Future Direct Searches with Benchmark-free Forecasting

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    Forecasting the signal discrimination power of dark matter (DM) searches is commonly limited to a set of arbitrary benchmark points. We introduce new methods for benchmark-free forecasting that instead allow an exhaustive exploration and visualization of the phenomenological distinctiveness of DM models, based on standard hypothesis testing. Using this method, we reassess the signal discrimination power of future liquid Xenon and Argon direct DM searches. We quantify the parameter regions where various non-relativistic effective operators, millicharged DM, and magnetic dipole DM can be discriminated, and where upper limits on the DM mass can be found. We find that including an Argon target substantially improves the prospects for reconstructing the DM properties. We also show that only in a small region with DM masses in the range 20-100 GeV and DM-nucleon cross sections a factor of a few below current bounds can near-future Xenon and Argon detectors discriminate both the DM-nucleon interaction and the DM mass simultaneously. In all other regions only one or the other can be obtained.Comment: 5 pages, 4 figures + appendices. Code for the calculations throughout the paper can be found at https://github.com/tedwards2412/benchmark_free_forecasting/ . v2: Minor corrections, matches version published in PRL as "Assessing Near-Future Direct Dark Matter Searches with Benchmark-Free Forecasting

    Digging for Dark Matter: Spectral Analysis and Discovery Potential of Paleo-Detectors

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    Paleo-detectors are a recently proposed method for the direct detection of Dark Matter (DM). In such detectors, one would search for the persistent damage features left by DM--nucleus interactions in ancient minerals. Initial sensitivity projections have shown that paleo-detectors could probe much of the remaining Weakly Interacting Massive Particle (WIMP) parameter space. In this paper, we improve upon the cut-and-count approach previously used to estimate the sensitivity by performing a full spectral analysis of the background- and DM-induced signal spectra. We consider two scenarios for the systematic errors on the background spectra: i) systematic errors on the normalization only, and ii) systematic errors on the shape of the backgrounds. We find that the projected sensitivity is rather robust to imperfect knowledge of the backgrounds. Finally, we study how well the parameters of the true WIMP model could be reconstructed in the hypothetical case of a WIMP discovery.Comment: 14 pages, 5 figures, code available at https://github.com/tedwards2412/paleo_detectors/ . v2: Added additional analysis theory details, matches version published in PR

    Transient Radio Signatures from Neutron Star Encounters with QCD Axion Miniclusters

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    The QCD axion is expected to form dense structures known as axion miniclusters if the Peccei-Quinn symmetry is broken after inflation. Miniclusters that have survived until today will interact with neutron stars (NSs) in the Milky Way to produce transient radio signals from axion-photon conversion in the NS magnetosphere. We quantify the properties of these encounters and find that they occur frequently (O(1100)day1\mathcal{O}(1-100)\,\mathrm{day}^{-1}); last between a day and a few months; are spatially clustered towards the Galactic center; and can reach observable fluxes. These radio transients are within reach of current generation telescopes and therefore offer a promising pathway to discovering QCD axion dark matter.Comment: 11 pages, 5 figures. Code is available online at https://github.com/bradkav/axion-miniclusters/ (archived at https://doi.org/10.5281/zenodo.4006128 ). Joint submission with "Stellar Disruption of Axion Miniclusters in the Milky Way" in astro-ph (arXiv:2011.05377). Updated to match published versio

    Stellar Disruption of Axion Miniclusters in the Milky Way

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    Axion miniclusters are dense bound structures of dark matter axions that are predicted to form in the post-inflationary Peccei-Quinn symmetry breaking scenario. Although dense, miniclusters can easily be perturbed or even become unbound by interactions with baryonic objects such as stars. Here, we characterize the spatial distribution and properties of miniclusters in the Milky Way (MW) today after undergoing these stellar interactions throughout their lifetime. We do this by performing a suite of Monte Carlo simulations which track the miniclusters' structure and, in particular, accounts for partial disruption and mass loss through successive interactions. We consider two density profiles - Navarro-Frenk-White (NFW) and Power-law (PL) - for the individual miniclusters in order to bracket the uncertainties on the minicluster population today due to their uncertain formation history. For our fiducial analysis at the Solar position, we find a survival probability of 99% for miniclusters with PL profiles and 46% for those with NFW profiles. Our work extends previous estimates of this local survival probability to the entire MW. We find that towards the Galactic center, the survival probabilities drop drastically. Although we present results for a particular initial halo mass function, our simulations can be easily recast to different models using the provided data and code. Finally, we comment on the impact of our results on lensing, direct, and indirect detection.Comment: 31 pages, 18 figures. Code available online at https://github.com/bradkav/axion-miniclusters/ (archived at https://doi.org/10.5281/zenodo.4006128 ). Joint submission w/ "Transient Radio Signatures from Neutron Star Encounters with QCD Axion Miniclusters", arXiv:2011.05378 . v2: Minor changes and references added. v3: Updated to match version published in PR

    Continuidad y cambio. Problemas de la neolitización en el este de la Península Ibérica

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    This paper analyses the transition from a hunter-gatherer economy to another one based on agriculture and animal-husbandry in the eastern part of the Iberian Península. Based on a comparative study of epipaleolithic and early neolithic sites with radiocarbon dates and/ or studies of fauna or cereals finds, we propose three models to explain the archaeological record.Se analiza la transición de una economía de cazadores y recolectores a otra basada en la agricultura y el pastoreo en la zona este de la Península Ibérica. Partiendo de un estudio comparativo de los yacimientos del Epipaleolítico y Neolítico antiguo con dataciones de carbono- 14 y/o estudios de fauna y hallazgos de cereales se proponen tres modelos para explicar el registro arqueológico

    Based Upon Repeat Pattern (BURP): an algorithm to characterize the long-term evolution of Staphylococcus aureus populations based on spa polymorphisms

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    Mellmann A, Weniger T, Berssenbrügge C, et al. Based Upon Repeat Pattern (BURP): an algorithm to characterize the long-term evolution of Staphylococcus aureus populations based on spa polymorphisms. BMC MICROBIOLOGY. 2007;7(1):98.Background: For typing of Staphylococcus aureus, DNA sequencing of the repeat region of the protein A ( spa) gene is a well established discriminatory method for outbreak investigations. Recently, it was hypothesized that this region also reflects long-term epidemiology. However, no automated and objective algorithm existed to cluster different repeat regions. In this study, the Based Upon Repeat Pattern ( BURP) implementation that is a heuristic variant of the newly described EDSI algorithm was investigated to infer the clonal relatedness of different spa types. For calibration of BURP parameters, 400 representative S. aureus strains with different spa types were characterized by MLST and clustered using eBURST as "gold standard" for their phylogeny. Typing concordance analysis between eBURST and BURP clustering ( spa-CC) were performed using all possible BURP parameters to determine their optimal combination. BURP was subsequently evaluated with a strain collection reflecting the breadth of diversity of S. aureus (JCM 2002; 40: 4544). Results: In total, the 400 strains exhibited 122 different MLST types. eBURST grouped them into 23 clonal complexes (CC; 354 isolates) and 33 singletons (46 isolates). BURP clustering of spa types using all possible parameter combinations and subsequent comparison with eBURST CCs resulted in concordances ranging from 8.2 to 96.2%. However, 96.2% concordance was reached only if spa types shorter than 8 repeats were excluded, which resulted in 37% excluded spa types. Therefore, the optimal combination of the BURP parameters was "exclude spa types shorter than 5 repeats" and "cluster spa types into spa-CC if cost distances are less than 4" exhibiting 95.3% concordance to eBURST. This algorithm identified 24 spa-CCs, 40 singletons, and excluded only 7.8% spa types. Analyzing the natural population with these parameters, the comparison of whole-genome micro-array groupings ( at the level of 0.31 Pearson correlation index) and spa-CCs gave a concordance of 87.1%; BURP spa-CCs vs. manually grouped spa types resulted in 95.7% concordance. Conclusion: BURP is the first automated and objective tool to infer clonal relatedness from spa repeat regions. It is able to extract an evolutionary signal rather congruent to MLST and micro-array data
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